The U.S. National Highway Traffic Safety Administration (NHTSA) is planning to prepare an Environmental Impact Statement (EIS) to analyze the potential environmental impacts of new fuel-efficiency standards for commercial medium- and heavy-duty on-highway vehicles and work trucks, potentially covering engines, chassis, vehicles, and/or trailers manufactured after model year 2018. NHTSA is inviting participation from all federal, state, and local agencies, Indian tribes, stakeholders, and the public to help identify significant issues and alternatives to be examined in the EIS. NHTSA, with the help of participants, also seeks to eliminate issues from the study that are not deemed significant. In a culmination of the scoping process, a Draft EIS will be made available for public comment. To prepare the draft, NHTSA is requesting all scoping comments be received on or before August 8. Participants are asked to submit comments through the Federal eRulemaking Portal, mail, hand delivery or courier, or by fax and include Docket No. NHTSA-2014-0074 with the comments.